1. Field of the Invention
The field of the invention is safety syringe needle covers or sheaths. Due to the possible presence of various infectious agents, there are grave dangers associated with unprotected post-use syringe needles. The subject device lowers the probability of these infectious agents being transmitted to a post-use handler of the needle mounted syringe via a needle prick by permitting the user to immediately cover the needle with a locking cover or sheath.
2. Description of the Background Art
Traditionally, devices that have been designed to protect users and others from syringe mounted needles have focused on protecting either the free, unattached needle or when the needle is associated with a syringe. However, when the device is incorporated into the outer barrel of a syringe, the protection device is very complex, costly to produce, subject to accidental complete removal by applying too much force in extending the protective cover, or not easily assembled by the manufacturer for production and shipment to consumers.
Disclosed in the patent from Norway, No. 96637, is a typical needle cover that latches directly onto the surrounding support of the needle and not the syringe. The cover is held in place by a simple pressure fit between mated teeth. To employ the cover the user must insert the needle tip into a relatively small cover opening without pricking themselves during the motion where the needle tip approaches their hand.
The patent from Great Britain, No. 1,191,634, relates a pair of covers that protect a double-pointed-ended needle intended for use with a tubular-vial syringe. Bayonet mounts are placed proximate both ends of a double-pointed-ended needle. Appropriately mated bayonet mount covers fit over the needle ends for protection.
U.S. Pat. No. 3,890,971 discloses a safety syringe for one time use. A sheath slides between inner and outer cylinders and is held in an extended, safety locked position by mating indents on the sheath with detents on the inner and outer cylinders. Further, the plunger is lockable after delivering a plunger piston to the bottom of an ampul that is fitted with the syringe and carries the injectable solution.
A shielded needle mounted to a syringe is described in U.S. Pat. No. 4,631,057. A cylindrical guard having on the interior a conical cam surface and bearing teeth at one end and an annular rib at the other. The syringe barrel has a collar proximate its needle that receives the upper ledge of the cam surface under a shoulder of the collar when the guard is extended. The teeth aid in preventing the guard from coming completely off the syringe by catching an annular groove that normally functions to hold the guard in the non-extended position by mating with the annular rib of the guard.
Disclosed in U.S. Pat. Nos. 4,752,290 and 4,826,491, both to Schrann for slightly modified inventions, is a needle bearing medical device with a three-position shield. The device presents a shield that may be positioned in fully extended, fully retracted, and an intermediate location about the syringe. A protective cap fits over the end of the shield and must be removed before use. Either an annular rib or downwardly disposed teeth, or a tooth, on the syringe mate with upwardly disposed teeth on the shield to secure the positions. A cut-out in the shield permits the required longitudinal movement.
U.S. Pat. No. 4,747,837 relates a syringe needle recapping protective device. An annular flange or multiple teeth secured to the inner lining of the sleeve lock the sleeve over a needle by being lodged between two annular locking ribs or teeth located of the barrel of the syringe proximate the needle.
A shielded safety syringe is depicted in U.S. Pat. No. 4,790,827. Various axially locking designs are presented for securing a protection sleeve over a needle attached to a syringe tip. An extendable and retractable sleeve has means for being secured in covered and protected positions. An inwardly projecting means from the sleeve, rides over and drops behind a stop member to anchor the sleeve in either the extended or retracted positions.
A protective device directly associated with a syringe needle is disclosed in U.S. Pat. No. 4,823,696. A protective guard telescopes over the needle after use. The protective guard is secured to needle itself and not directly to the syringe.
British Patent No. 2,209,946 relates a needle safety device. The device is a concentric series of interlocking cylinders that attach proximate the needle attachment point on a syringe and telescope over the needle. The protective cylinders are not associated with the outer portion of the syringe barrel.